The research proposed here investigates the effects of gonadal steroid hormones on mammalian social behavior, particularly aggression, sexual behavior and social signalling (scent marking). Mongolian gerbils were selected as model species. Manipulations of steroid hormone levels by gonadectomy, systemic injections and intracranial applicaton are being used to determine to what extent these three behavior patterns can be distingquished in terms of their hormonal bases and their neural sites of hormonal control. The same techniques are also to gather information on neural mechanisms of hormone action including specificity of steroid structure, the role of RNA synthesis and the effects of variations in neurotransmitter activityy. Other studies employ stimulus generalization techniques to determine more precisely what pheromonal cues gerbils attend to in situations where odors seemingly elicit specific behavioral responses. BIBLIOGRAPHIC REFERENCES: Yahr, P. (1976). Effects of hormones and lactation on gerbils that seldom scent mark spontaneously. Physiol. Behav., in press. Yahr, P. (1976). The role of aromatization in androgen stimulation of gerbil scent marking. Horm. Behav., in press.